Efficient integration of steam generating heat pumps by adapting to industrial process needs

In Austria, 57% of industrial process heat was generated with fossil fuels in 2020 [1]. To achieve decarbonization targets, this share must be significantly reduced. Waste heat valorization and thus efficiency increase with heat pumps pose a promising opportunity. In an IEA roadmap [2], it is stated that to achieve the net zero emission target by 2050, about 500 MWth of heat pumps should be installed every month for 30 years. Steam generating heat pumps in particular can make an important contribution, as steam is an often used process or heat transfer medium in the energy intensive industry. This contribution analyses different concepts how to integrate a steam generating heat pump into an industrial process. Industrial processes often require not only steam but also hot water at various temperature levels. Thus, not only steam generation, but also the simultaneous heating of water at a lower temperature level by means of a subcooler integrated into the refrigeration cycle is considered. This adaption compared to sole steam generation not only increases the efficiency of the heat pump, but also further reduces the use of fossil fuels. Moreover, a heat pump concept is being investigated that additionally generates hot water at a higher temperature level than in the subcooler. This can be achieved, for example, by integrating an additional condenser e.g. arranged in parallel to the condenser for steam generation. This concept allows the operating hours of the heat pump to be increased if one of the two process media (steam or hot water) is not always required. Models were created in IPSEpro for the investigations of the above described different concepts. The simulation results for the concepts are compared in terms of Coefficient of Performance, energy savings and CO2 savings per year. The contribution emphasizes that significant efficiency improvements of a heat pump system can be achieved by adapting the refrigeration cycle to the process conditions. This has great relevance for the integration of steam generating heat pumps in industrial processes.